This invention relates to a spray dispenser, and more particularly, to a motor driven spray gun for dispensing a liquid such as paint. Although paint is a specific example of a type of liquid which can be dispensed by the apparatus of the present invention, it is to be understood that other liquids may also be dispensed and that no limitation with respect to paint is intended.
In prior art dispensing apparatus, such as U.S. Pat. No. 3,455,507 to Ryder and Brouwer, the paint is held in a receptacle detachably connected to a housing. A partition wall extends across the housing, and a flange depends from the partition wall. The paint is sprayed outwardly by a spraying disk affixed to the shaft of a motor for driving the disk. The underside of the disk is spaced above the upper edge of a bushing which is supported on the hub of a support plate secured to a lower flange portion of the housing. The bushing cooperates with the disk to define a metering opening through which the paint is forced by a screw conveyor. The dimension of the metering opening is regulated by moving the spraying disk axially. The parts of the apparatus that must be moved to move the disk axially are free of the paint and easily movable. The paint is sprayed outwardly and exits the apparatus through an opening in the lower flange portion of the housing, the sides of the opening being adjustable by a movable gate which is mounted to the apparatus. A deflector shield is mounted between the partition wall and the support plate to intercept excess paint and direct the paint back into the receptacle.
The disadvantages of the above-described apparatus are the tolerance problems in initially setting the metering opening at the zero position, and the difficulty of cleaning the apparatus because the deflector shield, the screw conveyor, and the bushing, as well as the movable gate, are separate parts which are mounted to the spray dispenser.